All the above advice taken greatly to heart, but... I'm still missing something here. I understand needing only enough foil-relative-to-stay travel to get maximum turnbuckle take-up, but how do you adjust said turnbuckle when you can't get a wrench on the upper fitting? Is it intended that you only use the headstay turnbuckle to coarsely adjust length with the foil on the ground?
I sure don't like a halyard restrainer, believe me. It would be a temporary "solution" at best. My masthead is so tiny, the stay might as well be coming over the sheave with the halyard, they're that close together. I feel like the halyard would have to be two-blocked to eliminate the wrap. Hoisting, the halyard visibly bends around the puck (chafe chafe chafe)... Of course, once hoisted, the swivel tang, not the halyard, rests on the puck. I feel like the halyard lead needs to be shifted just a few degrees in any event.
Say Brian, think you can send me another foot of foil down with that Battslide?
Hate to chop up a brand-new stay, but it sounds like that's really the best option, no?